Hostname: page-component-cd9895bd7-gxg78 Total loading time: 0 Render date: 2024-12-28T02:05:48.121Z Has data issue: false hasContentIssue false

On the notion of a first neighbourhood ring with an application to the AF + BΦ theorem

Published online by Cambridge University Press:  24 October 2008

D. G. Northcott
Affiliation:
The UniversitySheffield

Extract

In an earlier paper (3) the author developed a theory of the neighbourhoods of a local domain, in which the concept of the first neighbourhood ring played a central role. This notion has since proved useful in connexion with certain one-dimensional problems, but it has emerged, in the process, that a considerable advantage would be gained if the theory could be freed from the assumption that the basic ring was to be without zero-divisors. This parallels the situation in the geometry of plane curves, where it is desirable, so far as is possible, that results and methods should apply with equal facility to reducible as well as to irreducible curves. Accordingly Part I of the present paper is devoted to a fresh account of the first neighbourhood ring from a more general standpoint than that used previously. Besides the greater generality thus obtained, the theory is extended by the addition of some new results. Furthermore, the proof of one of the main results of the original paper ((3), Theorem 10) has been considerably simplified. Of course, the ideas of (3) reappear here in a modified form, but, to spare the reader the irritating fragmentation of the subject which would otherwise be necessary, the revised account has been made independent of the earlier one. To this extent, Part I is self-contained.

Type
Research Article
Copyright
Copyright © Cambridge Philosophical Society 1957

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

(1)Krull, W.Dimensionstheorie in Stellenringen. J. reine angew. Math. 179 (1938), 204–26.CrossRefGoogle Scholar
(2)Northcott, D. G.Hilbert's function in a local ring. Quart. J. Math. (2) 4 (1953), 6780.CrossRefGoogle Scholar
(3)Northcott, D. G.The neighbourhoods of a local ring. J. Lond. Math. Soc. 30 (1955), 360–75.CrossRefGoogle Scholar
(4)Northcott, D. G.On homogeneous ideals. Proc. Glasg. Math. Ass. 2 (1955), 105–11.CrossRefGoogle Scholar
(5)Northcott, D. G.Abstract dilatations and infinitely near points. Proc. Camb. Phil. Soc. 52 (1956), 176–97.CrossRefGoogle Scholar
(6)Northcott, D. G. and Rees, D.A note on reductions of ideals with an application to the generalized Hilbert function. Proc. Camb. Phil. Soc. 50 (1954), 353–9.CrossRefGoogle Scholar
(7)Samuel, P. La notion de multiplicité en algèbre et en géométrie (Thesis, Paris, 1951).Google Scholar
(8)Severi, F.Trattato di geometria algebrica, 1 (Bologna, 1926).Google Scholar